Biomedical subjects
Publications and source records attributed to R Ansorg.
Bacteriophages in different stages of maturation were found in thin sections of a clinical isolate of Helicobacter (Campylobacter) pylori. Mature phage heads measured 70 x 60 nm and the tail at least 120 nm. Lysogeny was maintained during subculture on blood agar for more than 3 months after isolation from a gastric biopsy.
Using a broth microtiter dilution method, minimum inhibitory (MIC) and minimum bactericidal concentrations (MBC) were determined for the aminothiazolyl cephalosporins cefpirome and cefotaxime against 436 blood culture isolates. At concentrations of less than or equal to 16 mg/l, cefpirome inhibited 82.3% of the isolates and cefotaxime 66.5%. At the same concentrations, cefpirome killed 60.0% of the isolates and cefotaxime 46.7%. Whereas the MIC values indicated a far better activity of cefpirome than cefotaxime against oxacillin-resistant Staphylococcus aureus, Enterococci and Pseudomonas aeruginosa, the MBC values showed a poor activity of both drugs against these strains. By comparison, cefpirome was the more active agent, covering a similar spectrum to that of cefotaxime with a slight additional activity against oxacillin-susceptible S. aureus and Staphylococcus epidermidis.
Using a broth microtiter dilution method, the minimum inhibitory (MIC) and minimum bactericidal concentrations (MBC) of so-called antipseudomonal antibiotics were determined against 79 Pseudomonas aeruginosa isolates from cystic fibrosis patients. On the basis of the MIC values and using DIN breakpoints, the percentual susceptibilities led to the following rank order: imipenem (91%), ciprofloxacin (90%), tobramycin (87%), amikacin (87%), ceftazidime (82%), cefsulodin (76%), piperacillin (71%), azlocillin (62%), followed by gentamicin, ceftriaxone, mezlocillin, netilmicin, and cefotaxime (less than 50%). However, evaluating MBC values according to DIN breakpoints, only ciprofloxacin (82%), tobramycin (77%), amikacin (58%), and imipenem (57%) showed a pronounced antipseudomonal effectiveness. The data indicate that MBC determinations are necessary to evaluate the antibiotic susceptibility of P. aeruginosa rather than MIC determinations, at least in patients with impaired defence mechanisms which require bactericidal therapy.
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A model of experimental keratomycosis in the rabbit eye is described. Candida albicans strain DSM 70010 (10 microliters; 2.5 X 10(5) cells) is injected intracorneally without employing immunosuppressive measures. This strain is characterized by marked germ-tube formation, which apparently is a major cause of its virulence. All 17 eyes developed an infiltration of the cornea two days after injection. On Day 6 (mean value; standard error +/- 2.34 days) this infiltration developed synchronously to a severe corneal ulcer with hypopyon. The infection remained active for about two weeks and was either complicated by a descemetocele or perforation or led to a reparatory stage with extensive vascularization and successive leukoma. The model presented is reproducible for the first time and is therefore recommended for experimental evaluation of new therapeutic concepts.
The efficiency of Amphotericin B drops was studied using a newly developed keratomycosis model (defined strain Candida albicans DSM 70010, which leads reproducibly to a corneal infection with descemetocele without prior local or systemic immunosuppression in the rabbit). Penetration of the drug (administered ten times a day) into the cornea and aqueous humor was only demonstrated after abrasion of the corneal epithelium. Three groups were studied: (I) therapy with abrasion, (II) therapy without abrasion, and (III) a control group. Both clinically (descemetocele or perforation, hypopyon) and with regard to microbiology (reculture of Candida) the results obtained in Group I were significantly better than those obtained in Group II (p less than 0.001). Repeated corneal abrasion is therefore recommended for treatment of Candida keratitis with Amphotericin B.
To evaluate the risk of acquiring TBE in the Saarland, tick-borne encephalitis (TBE) antibodies were investigated in the sera of 408 persons working in forestry, 44 patients with suspected viral infection of the central nervous system, and of 439 animals which had been particularly exposed to ticks. A complement fixation test was used for all sera. The human sera were additionally tested with an enzyme-linked immunosorbent assay. TBE antibodies were found in eight forestry employees who had been vaccinated against TBE. All other persons as well as the animals did not show TBE antibodies. The very low antibody rate in the risk groups indicates that the Saarland is free of natural foci of TBE. At present, there is no argument for a general TBE immunprophylaxis in that area.
The investigation of postmortem human tissue, exposed to the influence of flies and their maggots, has shown in general that there is a drop in ABO blood-group activity due to the secretive action of the anterior intestinal gland of the larva. In addition, the phenomenon of acquired heterogeneous blood-group-specific substances was observed. By analogy with the findings in mummy tissues, the postmortal invasion of foreign bacterial and fungal blood-group-active material is discussed as a cause of erroneous serological diagnosis in bones. Acquisition of foreign serological activity through plant saprophytes was detected in a bone sample infested with algae. In different subfossil bone samples, blood-group activity was evident in the more decomposed areas, while in the better preserved parts of the bony substance, negative reactions were obtained.
An enzyme-linked immunoassay was used to determine serum content of IgG and IgM antibodies against eight capsular polysaccharides of Streptococcus pneumoniae in 19 patients with chronic obstructive lung diseases 3 years after inoculation with a polyvalent pneumococcal vaccine (Moniatrix); 21 unvaccinated patients with comparable diseases served as the control group. The vaccinated group showed slightly more pronounced IgG antibody reactions than the unvaccinated group, but the differences were not statistically significant. These results show that pneumococcal vaccination does not provide long-term protection at least for patients with chronic obstructive lung disease.
27 patients received either 4 g intravenous infusion 1-3 h or 100 mg subconjunctival application of mezlocillin 1-12 h before cataract extraction. After intravenous administration the mean aqueous humour concentration of mezlocillin was 2.9 micrograms/ml after 2 h. The subconjunctival dose produced a mean aqueous humour concentration of 23 and 2.6 micrograms/ml after 3 and 12 h, respectively. These levels are above the minimum inhibitory concentration of mezlocillin for sensitive organisms.
The actual intake of antibiotics was tested in patients who were or were not known to be on antibiotic prescriptions. Using the B. subtilis (ATCC 6051) inhibitory test, the presence of antibiotics in the urine can be demonstrated specifically and at low concentrations. Of 2700 patients not known to be taking antibiotics, 8% had antibiotics in their urine. Of 400 patients with written prescriptions for antibiotics 25% had no antibiotic activity in urine. In order to avoid treatment failures, regular control of medications with the B. subtilis inhibitory test should be undertaken, especially in patients receiving oral chemotherapy.
Determination of the somatic (O-) antigens of Pseudomonas aeruginosa by conventional slide agglutination is frequently complicated by the barely discernible, slow reaction of native cells. For diagnostic purposes a more practical procedure, a coagglutination test, has been developed in which protein A bearing Staphylococcus aureus (ATCC 12598) cells are added to the agglutination process occurring between specific anti-O serum and native Pseudomonas aeruginosa. Compared to the conventional method, slide O-coagglutination yields larger agglutinates in a shorter mean reaction time, i.e. one minute vs four minutes. Moreover, strains not reacting in the O-agglutination method or reacting only with polyvalent anti-O serum can be grouped by O-coagglutination, and cross reactions between reference strains of different O-groups do not occur. This method facilitates O-grouping of Pseudomonas aeruginosa in epidemiological investigations.
Twenty-nine patients received either 4 g intravenous infusion or 100 mg subconjunctival application of azlocillin 1-12 h before cataract extraction. After intravenous application the mean aqueous humor concentration of azlocillin was 4.4 micrograms/ml after 3 h. The subconjunctival dose produced a mean aqueous humor concentration of 78 micrograms/ml and 3.4 micrograms/ml after 3 and 12 h, respectively. These levels are above the minimum inhibitory concentration of azlocillin for sensitive organisms.
The penetration of cefotaxime, a new semi-synthetic cephalosporin, into human aqueous humour was investigated. Doses of 1 g (17 patients) and 2 g (19 patients) were administered intravenously at time intervals varying from 45 min to 4 h prior to routine cataract surgery. After the 2 g dosage the average concentration of cefotaxime in the aqueous humour was higher (P less than 0.05) and lasted longer than after the 1 g dosage. The highest average concentration in the aqueous humour after the 1 g dosage was 1.85 microgram/ml, 3.95 micrograms/ml after the 2 g dosage. Therapeutic levels were consistently found in both groups for the organisms most commonly responsible for bacterial endophthalmitis, except for Pseudomonas aeruginosa and Staphylococcus epidermidis.
The Candida colonization and the dynamics of antibodies to Candida were studied in intensive care patients. 20 patients received no antifungal prophylaxis, 20 patients were treated by local application of Pimaricin into the mouth, nose, and into the respiratory tract during the time of intratracheal intubation. The frequencies and quantities of yeasts in the respiratory secretions were considerably reduced in the group receiving Pimaricin, whereas the amount of faecal colonization showed no difference between both groups of patients. During the 2nd-3rd week of hospitalization 17 patients of the untreated group and 4 patients of the treated group developed a significant rise of Candida antibodies. The association between the respiratory colonization and the antibody response indicates that the mucosa of the mouth and the respiratory tract is a main source of Candida invasion. In order to prevent that precondition of Candida endomycosis, routine ororespiratory antifungal prophylaxis is recommended, particularly in patients with prolonged intratracheal intubation.
During April/Mai 1982 15 patients were affected with acute Malta fever around Goettingen an area known the be brucellosis-free until then. The source of infections were local flocks of sheep. The infections were mainly acquired when assisting at lamb birth or abortions. Between onset and diagnosis of the disease intervals up to 3 month occurred. Diagnostically crucial were blood cultures and serological tests. Therapy with tetracyclines or co-trimoxazole were effective in all cases. In patients with status febrilis and anamnestic contact with brucellosis-prone animals brucellosis should be considered, even if the local area appears to be brucellosis-free.
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